The present invention relates to a semiconductor apparatus sealed with resin and a method for producing the same.
Conventionally, a wire bonding type semiconductor apparatus comprises a metal lead frame and a semiconductor chip. The metal lead frame has a bed, an inner bed, and an outer lead, each of which is integrally constructed therewith. The semiconductor chip is mounted on a bed. The semiconductor chip and the inner lead are connected through a bonding wire. The semiconductor chip, the bonding wire, and their neighboring portions are sealed with a plastic resin.
As the integration and processing speed of semiconductor apparatuses increase, they proportionally increase the heat generated. Thus, the heat generated by the semiconductor chip should be effectively radiated.
Another wire bonding type semiconductor apparatus is known which effectively radiates the heat generated therefrom. This wire bonding type semiconductor apparatus has a bed on which a semiconductor chip is mounted, the size of the bed being much larger than that of the semiconductor chip, the bed being extended nearly to each outer edge of a plastic resin. According to this wire bonding type semiconductor apparatus, since the large bed having high thermal conductivity is in contact with the semiconductor chip which radiates heat in the plastic resin having low thermal conductivity, the heat generated in the semiconductor chip can be effectively radiated.
However, as the size of the bed becomes large, the distance between the semiconductor chip and the inner lead becomes large. Thus, since the length of the bonding wire between the semiconductor chip and the inner lead proportionally becomes large, the bonding wire may occasionally contact the bed and therefore result in electric leakage.
On the other hand, a TAB type semiconductor apparatus is known. The TAB type semiconductor apparatus comprises a metal lead frame and a TAB tape. The metal lead frame has a middle lead and an outer lead. The TAB tape has an inner wire and a middle wire. The inner wire and the middle wire are connected through a connection wire. A semiconductor chip is connected to the inner wire through a bump. The middle wire of the TAB tape is connected to the middle lead of the lead frame. The semiconductor chip, the TAB tape, and their peripheral portions are sealed with a plastic resin.
Then, a method for producing the TAB type semiconductor apparatus is described below.
First, a substrate made of a polyimide is prepared. After this substrate is punched out, it is laminated with a copper foil. Thereafter, the copper foil is photo-patterned, etched, and then plated. Thereby, a TAB tape is produced.
A conventional wafer can be prepared. Thereafter, a bump forming process and a probing process are performed on the wafer. Thereby, a semiconductor chip is produced.
In addition, a metal material is prepared. For this metal material, a photo-pattern process, an etching process, and a plating process are performed. Thereby, a lead frame is produced.
Thereafter, the semiconductor chip and the inner wire of the TAB tape are connected through the bump. Thereafter, an outer portion of the middle wire of the TAB tape is cut so as to expose the middle wire to the outside.
Thereafter, the middle wire of the TAB tape and the middle lead of the lead frame are connected. Thereafter, the semiconductor chip, the TAB tape, and their neighboring portions are sealed with a plastic resin.
Thereafter, for the semiconductor chip and the TAB tape, which are sealed, a sheathing process and an outer lead forming process are performed. Thereby, a TAB type semiconductor apparatus is produced. Thereafter, for the semiconductor apparatus, a verification process is performed.
Since the semiconductor chip of the TAB type semiconductor apparatus is not in contact with the metal lead frame, heat generated in the semiconductor chip is radiated through the plastic resin having low thermal conductivity. Thus, the thermal radiating property of the TAB type semiconductor apparatus is not high.
As described above, when the size of the bed of the wire bonding type semiconductor apparatus is large, the bonding wire becomes accordingly very long. Thus, the bonding wire may occasionally contact the bed, resulting in electric leakage.
In contrast, the TAB type semiconductor apparatus is free from the problem of electric leakage. However, the heat generated in the semiconductor chip is radiated through the plastic resin having low thermal conductivity. Thus, the thermal radiating property of the TAB type semiconductor apparatus is low.